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Book Geotechnical Aspects of Rock Erosion in Emergency Spillway Channels

Download or read book Geotechnical Aspects of Rock Erosion in Emergency Spillway Channels written by United States. Department of the Army. Corps of Engineers. Geotechnical Laboratory and published by . This book was released on 1986 with total page 131 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Geotechnical Aspects of Rock Erosion in Emergency Spillway Channels

Download or read book Geotechnical Aspects of Rock Erosion in Emergency Spillway Channels written by Christopher C. Mathewson and published by . This book was released on 1998 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study addresses the geologic factors that control rock erosion in emergency spillway channels, develops a technique to evaluate the risk and predict the potential erosion of rock and soil exposed to hydraulic attack during a flow event in the channel, and provides design concepts for the repair and rehabilitation of spillway erosion.

Book Repair Evaluation Maintenance and Rehabilitation Research Program Geotechnical Aspects of Rock Erosion in Emergency Spillway Channels

Download or read book Repair Evaluation Maintenance and Rehabilitation Research Program Geotechnical Aspects of Rock Erosion in Emergency Spillway Channels written by Christopher O. Cameron and published by . This book was released on 1986 with total page 131 pages. Available in PDF, EPUB and Kindle. Book excerpt: Problems of rock erosion in unlined emergency spillway channels are described in this first-of-a series report. Recent case histories which illustrate the potentially hazard of excessive erosion in discharge channels are described as are various factors controlling erosion and other responses to emergency spillway overflow. Research to improve geotechnical capabilities with respect to selection of cost-effective preventive and remedial measures in discharge channels where the risk of excessive erosion appears high is also discussed. Response to emergency spillway overflow is controlled by such hydraulic and geologic factors as flood frequency and magnitude, engineering design, discharge channel gradient(s), discontinuity of earth materials, and erodibility of earth materials. A major controlling factor of erosion in spillway discharge channels lined by sedimentary strata appears to be the interrelated effect of stratigraphic discontinuity and channel gradient change(s). These factors combine to initiate and control headward migration of knickpoints, where resistant sedimentary layers are undercut by scouring of softer, underlying strata. In terms of erodability of earth materials, the scale of the hydraulic forces generated during emergency spillway overflows suggests that rippability and lithostratigraphic discontinuity may serve as a good point of departure in describing the relative resistance to erosion of rocks lining discharge channels.

Book Repair Evaluation Maintenance and Rehabilitation Research Program Geotechnical Aspects of Rock Erosion in Emergency Spillway Channels Report 2 Analysis of Field and Laboratory Data

Download or read book Repair Evaluation Maintenance and Rehabilitation Research Program Geotechnical Aspects of Rock Erosion in Emergency Spillway Channels Report 2 Analysis of Field and Laboratory Data written by Christopher P. Cameron and published by . This book was released on 1988 with total page 61 pages. Available in PDF, EPUB and Kindle. Book excerpt: Studies of erosion in unlined emergency spillways channels excavated in rock have demonstrated that erosional processes operating in these spillway channels are similar to those operating in natural stream channels and that rock discontinuities are critical factors in the initiation and extent of erosion. Knickpoint formation and headcutting are typical erosion processes. Fractures, faults, joints, dip orientation, igneous contacts, veins, bedding planes, unconformities, bed pinch outs, and facies changes are types of structural or stratigraphic discontinuities which must be characterized if present. Analysis of 14 Soil Conservation Service and 2 ACE dams which have experienced emergency spillway flow revealed that the extent of erosion at these sites could be categorized in terms of volumetric and horizontal erosion rankings. These ranking parameters provide insight as to the seriousness of the erosion threat at a particular dam and may be used to give priority for remediation. The ranking parameters were more closely correlatable with the geometry of the spillway channel than with the hydraulics of the spillway flow event. Preliminary laboratory studies demonstrated that maximum undermining and erosion of a stratified, two-layer system was a function of the ratio of water depth to knickpoint height and the venting condition of the waterfall. Maximum erosion did not occur at peak discharge but occurred when the discharge passed through windows or thresholds on the rising and falling limbs of the hydrograph which were, in turn, controlled by the ratio (above) and venting.

Book Repair Evaluation Maintenance and Rehabilitation Research Program Geotechnical Aspects of Rock Erosion in Emergency Spillway Channels Report 3 Remediation

Download or read book Repair Evaluation Maintenance and Rehabilitation Research Program Geotechnical Aspects of Rock Erosion in Emergency Spillway Channels Report 3 Remediation written by Christopher P. Cameron and published by . This book was released on 1988 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: Remediation of unlined emergency spillway erosion damage is a relatively new, but major, concern to the US ACE districts and to other dam owners and operators. Remediation design is highly site-specific and must be cost-effective, address public safety, and to provide continued reservoir operations. Selection of remedial technique(s) must be established by site- specific characterization of the rocks forming an unlined spillway channel in terms of rock composition(s), hardness, structural and stratigraphic discontinuities, and precursor erosion elements, all of which determine rock erodibility and its rate. Erosion probability indices based on methods which combine rock mass parameters (composition, hardness, structural discontinuity, etc.), which determine 'rippability, ' with lithostratigraphic continuity may allow for site-prioritization in terms of the need for remedial and preventive techniques. Potentially useful remedial techniques include cement-based methods such as grouting, shotcrete, soil cement/roll crete, and high-strength unreinforced and reinforced concrete, as well as rock bolts, wire mesh, gabions, and riprap. Potentially useful erosion preventive measures include construction of energy dissipators and cut-off walls and the removal of vegetation and other obstacles to flow. Flow rerouting, relief of uplift pressures, and placement of geotextiles and natural grasses (especially in poorly lithified rocks and soils) may also offer useful alternatives.

Book Repair Evaluation Maintenance and Rehabilitation Research Program Geotechnical Aspects of Rock Erosion in Emergency Spillway Channels Report 4 Geologic and Hydrodynamic Controls on the Mechanics of Knickpoint Migration

Download or read book Repair Evaluation Maintenance and Rehabilitation Research Program Geotechnical Aspects of Rock Erosion in Emergency Spillway Channels Report 4 Geologic and Hydrodynamic Controls on the Mechanics of Knickpoint Migration written by and published by . This book was released on 1989 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the last decade, occurrences of emergency spillway discharges at Soil Conservation Service, Corps of Engineers, and private reservoirs have increased and, in certain circumstances, resulted in erosional damages to the spillways. Rapid headward erosion in unlined emergency spillways at Corps of Engineers reservoirs including Grapevine, Saylorville, and Black Butte caused the Corps to take a serious look at the available methods used to predict erosion damage in unlined emergency spillways. The catastrophic loss of private and Soil Conservation Service reservoirs because of knickpoint migration in emergency spillway channels was additional evidence that the mechanics of knickpoint erosion were not clearly understood. Severe erosion was documented at several Corps spillways where the flow was less than one-tenth of the designed capacity. The purpose of this research was to study knickpoint erosion phenomena with respect to the combined effects of the geologic and hydrodynamic controls. In order to study the mechanisms working at the knickpoint, several obstacles had to be overcome. First a material had to be developed which would erode like rock but would keep the eroding water clear so that the failure mechanisms could be observed. Sodium silicate and gelatin-cemented gravel in combination with Plexiglass were used to simulate knickpoints in layered rock. Next, a hydraulic flume had to be modified to accommodate layered samples.

Book Recent Library Additions

Download or read book Recent Library Additions written by and published by . This book was released on 1985 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book List of Publications of the U S Army Engineer Waterways Experiment Station

Download or read book List of Publications of the U S Army Engineer Waterways Experiment Station written by U.S. Army Engineer Waterways Experiment Station and published by . This book was released on 1993 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book National Dam Safety Program

Download or read book National Dam Safety Program written by and published by . This book was released on 1992 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Santa Ana River Main Stem and Santiago Creek

Download or read book Santa Ana River Main Stem and Santiago Creek written by and published by . This book was released on 1978 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt: